Copending, commonly assigned U.S. Patent Application Ser. No. 6/099,838 filed Dec. 3, 1979 by John Engalitcheff, Jr. and now U.S. Pat. No. 4,337,050, the contents of which are incorporated by reference herein, describes a Method and Apparatus for the Rehabilitation of Damaged Limbs in which a plurality of interchangeable tool simulator accessories are detachably connected to a brake means having a constant, predetermined torque resistance for use in diagnostic and rehabilitation therapy of damaged upper extremeties. By simulating the natural movements of common activities under conditions of controlled torque resistance which remains linear rather than increasing with increased load, this device permits a gradual series of progressive exercises which can avoid muscle damage caused by trying to progress too quickly.
The device described therein employs a mechanical cam affixed to the rotating brake shaft which trips a microswitch to record the number of revolutions so as to enable the therapist to monitor the degree of exercise at each session. It has been found difficult to quantify such a registration technique and to distinguish between revolutions against applied torque resistance versus free-wheeling revolutions, which distinction is a valuable one for the therapist.